Sealing machine and method



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SEALING MACHINE AND METHOD Filed Feb. 5, 1960 8 Sheets-Sheet 8 SI I i 8Q 9 n E ,lllllllll-lllllllllllllllllll [F \RZ'w S 949) E. Srovee ZWQMMQAFTO P/YFY United States Patent 3,054,234 SEALING MACHINE AND METHODHarry E. Stover, Lancaster, Ohio, assignor to Anchor Hocking GlassCorporation, Lancaster, Ohio, a corporation of Delaware Filed Feb. 5,1960, Ser. No. 6,993 18 Claims. (Cl. 53-38) The present inventionrelates to the sealing art and more particularly to a machine and methodfor sealing screw caps, preferably the lug type, to containers.

Lug caps or closures are special types of screw caps in which lugs onthe closure engage corresponding threads or lugs on the container finishto pull the closure down at a plurality of points throughout thecircumference. This type of cap dilfers from the continuous thread capwhere a helical thread extends completely about the finish to mate witha corresponding helical thread extended entirely about the closure. Lugcaps may be screwed on in a fraction of a turn, usually a quarter turnfor large size caps or a one-half turn for small sizes; whereas,continuous thread caps require a complete turn.

Two general types of machines have been utilized for applying screwclosures to containers. The first type utilizes a turret and a series ofchucks for screwing the caps on. The second type utilizes a pair ofbelts or discs engaging opposite sides or top portions to screw theclosures into sealed position on containers which are moving forward ona straight conveyor. The belts or discs have to be driven at differentspeeds or in different directions to screw the caps on.

The present invention relates to the second type of machine and avoidsthe use of a pair of belts or discs and the necessity for a pair ofdrives for driving them at different speeds, or in opposite directionsto screw the caps on. The present invention provides a stationary shoeresiliently held in position to engage right elf-center portions (viewedfrom the entrance end of the machine) of the closures to quickly screwthe closures on as they move past the shoe while seated on containerscarried by a conveyor belt. A single belt with a single drive may engagethe left olfcenter portion of the closure to facilitate the operation.Thus, the sealing operation is simplified, wear is minimized, and asecure seal is obtained.

The invention also improves the seating and initial threading of theclosure on the finish by magnetically suspending the closures, freelymovable laterally in any direction at the time the closures aretelescoped onto the glass finish so that each closure may accuratelycenter itself on the threaded finish.

An object of the present invention is to provide an improved machine andmethod for applying screw closures, preferably of the lug type.

Another object of the invention is to provide a sealing machine andmethod for applying screw closures which is simple in design, readilyadjustable and effective in providing a secure seal.

Another object of the invention is to provide a sealing machine in whichwear, particularly wear on replaceable elements, is reduced to aminimum.

Another object of the invention is to provide an improved mechanism forseating and initially threading closures on containers.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description and is shown in the accompanying drawings,forming a part of the specification wherein:

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FIG. 1 is a side elevational view of a sealing machine in accordancewith the present invention;

FIG. 2 is a top plan view of the sealing machine of FIG. 1;

FIG. 3 is a perspective view of the closure applying means and thesealing means of the sealing machine of FIG. 1;

FIG. 4 is a sectional view of the sealing machine taken along lines 44of FIG. 8;

FIG. 5 is an enlarged detailed view of the sealing means of the sealingmachine of FIG. 1; I

FIG. 6 is a horizontal sectional view of the sealing means taken alonglines 66 of FIG. 5;

FIG. 7 is a vertical sectional view of the sealing means taken alonglines 77 of FIG. 5; 1

FIG. 8 is a plan view partially cut away of the sealing head of thesealing machine of FIG. 1 showing the side belts and the conveyor belt;

FIG. 9 is a side elevational view partially cut away of the sealing headshowing the sealing means; 7

FIG. 10 is an enlarged detailed view of the steam connections for themachine;

FIG. 11 is a sectional view taken along lines 1111 of FIG. 10;

FIG. 12 is a sectional view of the steam tunnel taken along lines 12-12of FIG. 10;

FIG. 13 is an enlarged detailed side elevational view of the capapplicator of the present invention;

FIG. 14 is a top plan view of the cap applicator of FIG. 13;

FIG. 15 is a sectional view of the cap applicator taken along lines15-15 of FIG. 13;

FIG. 16 is an enlarged detailed side elevational view of the sealingbelt and its mounting;

FIG. 17 is a fragmentary view of another embodiment of the capapplicator; and

FIG. 18 is a sectional view of the magnetic wheel taken along lines 1818of FIG. 13.

General Description The sealing machine will first-be describedgenerally with particular reference to FIGS. .1 through 4. Asillustrated in FIG. 1 the sealing machine 1 includes an endless conveyorbelt 2 mounted on a suitable base 3 0m end sprockets 4 and 5. Thismounting provides for a. horizontal upper run 6 of the conveyor belt 2over the top of base 3 so that the filled containers fed onto theconveyor belt 2 adjacent sprocket 4 are carried in succession beneaththe closure applying and sealing head indicated generally at 7. Asillustrated in FIG. 2 a suitable drive motor 8 is provided in the base 3which standard coupling means interconnecting the motor 8 and one orboth of the sprockets 4 and 5.

The improved closure applying andsealing head 7 is illustrated in FIG.3. As the filled containers 12 are moved by the conveyor 2 betweensuitable adjustable guide rails 9, the containers 12 first pass througha steam tunnel 10 which directs steam into the container head spaces todisplace the air and to provide a partial vacuum when the container isthereafter sealed. As the containers 12 leave the steam tunnel 10 theypass beneath a closure applicator indicated generally at '11. As will bemore fully described below, each of the containers 12 draws a closure 14from the applicator 11 so that the closure 14 is telescoped looselyabout the container mouth and is held in a level position above thecontainer mouth. Next the applicator presses the closure 14 lightly andlevelly downward while the closure is simultaneously given an initialslight rotation to cause an initial engagement between the threads ofthe closure 14 and the container 12. Thereafter the containers 12 passon conveyor 2 beneath the sealing means indicated generally at i wherethe closure 14 is simultaneously rotated and forced downwardly intotight sealing engagement with the container finish. -The improvedsealing means 15, which will be described in detail below, preferablycomprises an endless driven belt 16 and a fixed shoe 17. As illustratedin FIG. 4, the moving belt 16 contacts an outer portion of the top ofthe closure 14 and the fixed shoe 17 contacts an opposite portion of theclosure top. The belt 16 may be driven at a speed greater than that ofthe conveyor. The fixed shoe 17 provides a drag friction force on theclosure top. Thus, the combined effect of the opposite forces of thebelt 16 and the shoe 17 is a rotation drive which turns the closure 14downwardly onto the container threads while the gasket in the closure 14is pressed tightly against the container finish.

An elongated steam distributor 18, FIGS. 3 and 10, is positionedadjacent the sealing means 15 and parallel to the conveyor belt 2 toemit a sheet or cloud of steam from its elongated side port 19 toprovide a steam atmosphere surrounding the closures 14 and the tops ofthe containers 12 during the sealing operation. This prevents there-entrance of air into the containers before and during the sealingoperation to insure the completion of the seal without the re-entry ofair into the con-. tainer. After the sealed containers 12 move beyondthe sealing means 15, the cooling of the head space causes the steam tocondense and a partial vacuum to form within the head space.

As illustrated in FIG. 3, side belts 20 and 21 respectively are providedto engage the opposite sides of the containers 12 as they pass throughthe sealing head 7 on conveyor 2 to support the containers at theapplicator station and to prevent rotation of the containers as theclosures 14 are rotated into their sealed position. Each of the belts 20and 21 is mounted on a drive pulley 22 and on idler pulleys 23. Pulleys22 are driven by motor 8 to move the side belts 20 and 21 at the samespeed as the conveyor 2. Positioning pulleys 24 which are adjustablypositioned laterally of conveyor 2 are provided to hold the side belts20 and 21 inwardly against the moving containers 12 to position thecontainers 12 centrally beneath the closure applicator 11 and thesealing means 15 as illustrated in FIG. 4 and to move the containersforward at the speed of the conveyor 2.

The Closure Applicator The closure applicator 11 is illustrated indetail in FIGS. 13-45. As best seen in FIG. 13 the applicator comprisesan inclined cap chute having a channel 31 to slideably receive a line ofclosures 14 as they are fed into the top of the chute 30 by a suitablecap feed (not shown). The closures 14 slide downwardly in channel 31under the force of gravity until they reach the position of closure 14at the lower end 32. As illustrated in FIGS. 13 and 14, the closure 14is held in this lowermost position adjacent the lower end 32 by theinwardly spring biased pin members or detents 34.

At this point the closure 14 at the bottom 32 of the chute 30, with itslower side depending beyond it, is about to be engaged and removed fromthe chute by the container 12 engaging the overhanging skirt to pull itfrom the chute 30 past or over the biased pins or detents 34. Since theclosure 14' is to be screwed onto the con tainer, the lugs of theclosure 14 have to engage under the lugs or thread portions on the glassfinish, 35. If a lug on one side of the closure 14 engages under athread on the glass finish and the lug on the opposite side of theclosure 14' is on top of the thread on the finish a so-called cocked capresults. A cocked cap cannot be screwed on properly. Usually, thedownward pressure spreads the skirt of the cap to make the lug jump thethread and an imperfect seal results.

In order to prevent cocked caps and to initially thread the closure 14'onto the glass finish of container 12' so that the lugs on the closure14' all engage under the respective threads on the container, thepreferred embodiment of cap feed or applicator provides three elementsadapted to cooperate in leveling the cap 14 on the finish 35 and ininitially threading it on the container finish.

First (FIG. 13), a magnetic wheel 38 having magnets 38' engages thecover part of the closure 14' and suspends it with the front end inengagement with the front part of the finish. The wheel 38 holds the cap14 in an upper position to prevent al ug from prematurely engaging undera container thread and assists in the transfer of the closure 14' fromthe lower end of the chute 30 to the second element, that is, theleveling element 40 which also has a series of magnets 41 to hold thecap in raised position with the lower part telescoped over the containerfinish (FIG. 18). The third leveling element or plate 42 utilizes a pairof rails for initially threading the level cap 14" on the glass finish.

Where the closure 14' is kept in a horizontal or level position while itis pressed down on the glass finish there is no occasion for the closureto cock. It is held in level position to prevent one lug from gettingunder one thread and the opposite lug above the opposite thread on theglass finish.

These three elements for placing the closure on and initially threadingit to the container, will now be described in detail.

Referring further to FIGS. 13 and 14 the magnetic wheel 38 comprises apair of steel discs 37 spaced apart by a center disc of nonmagneticmaterial. The center disc may be Micarta, or a similar plastic material.A series of magnets 38 mounted in the center disc at its periphery havetheir poles in contact with the two discs 37, making them the north andsouth poles of a circular magnet and hence the edges of the discs 37will magnetically support or suspend the closure 14 as it passes fromthe lower end of the cap chute 30 to the first leveler 40. The cap 14 ispulled forward by being initially telescoped over the moving container12'. Preferably, the wheel 38 is as light as possible to minimize theeffect of inertia. The wheel 38 may be mounted at the bottom of thechute 30 directly above the moving containers 12' and closures 14', bythe arms 48 having bearings for the shaft 37' passing through the centerof the wheel 38. The arms 48' are secured to the leveling plate 40.

The first leveling plate 40 which receives the closures 14' as they passfrom the wheel 38 is pivotally mounted at shaft 47 on the end of capchute 30 and has an extension 48. The extension 48 is used to adjust theposition of the plate 40 by means of the adjustable limit screw 43 whichfits into slot 43 in its adjusted position and to permit an upwardtilting of the leveling plate 40 for off-size closures or containers orfor tilted containers. The leveling plate 40 is preferably given aslight downward slope to cause the closure to be lowered onto thecontainer finish as the container is moved toward the end of theleveling plate 40.

The third element 42 for initially threading the level closure 14" onthe finish is pivotally mounted on the cap chute 30 at 52 at the ends ofthe pair of arms 50 which are secured by pivotal connection 51 on thefront end of the leveler 42. Thus, initial threading plate 42 is pivotedat 51 to swing upwardly about a relatively short radius and is alsopivoted at 52 to move up as an entirety about a rather long radius. Thelower portion of the threading plate 42 has spaced rails 44 and 45 toengage the closure cap. The rail 44 has a smooth relatively frictionlesssurface while the rail 45 preferably has its lower surface 45' formed ofrubber or other friction material which serves to retard one side of theclosure to rotate it and to initially thread the closure on the finishwhile the rails 44 and 45 hold the closure level. The friction elementrail 45 turns the cap 14" to initially thread it onto the container 12"but the force exerted is not great enough to do more than to start thethreading operation. Since the cap 14" is kept horizontal on the finishwhen it reaches the threading member 42 and during its passage under therails 44 and 45 thereof, there is no tendency for the closures to cocand hence cocked caps are avoided.

An adjusting screw 54 on the plate 42 adjust-ably engages the upper sideof the leveling plate 40 to control the angular position of the frictionelement rail 45.

The closure applicator 11 is detachably mounted on the steam tunnelhousing by removal pins 57 and brackets 58 (FIG. 13).

Another embodiment of the cap applicator is illustrated in FIG. 17. Inthis cap applicator the coaxing plate 42 is pivotally mounted on the endof the leveling plate at? by means of the link 50' which is pivotallyattached to the coaxing plate 42 and the leveling plate 40' at pivots51' and 52 respectively. The coaxing plate 42' has parallel closure capengaging rails similar to those of the coaxing plate 42 with a frictionmember 45" attached to the lower surface of one rail to provide a dragforce to cause the initial light rotation of the closure 14 intoengagement with the threads of the containers 12 as the closure movesbeneath the coaxing plate 42.

The Container Sealing Means As described above, each of the containers12 is moved away from the closure applicator 11 with a closure 14applied to the top of the container and with the closure threads or lugslightly turned into an initial engagement with the container threads orlugs. The conveyor 2 now carries the containers 12 beneath the containersealing means which is illustrated in detail in FIGS. 3 through 8.

The container sealing means 15 comprises a moving endless belt 16 whichengages one off-center portion of the closure and a stationary shoemember 17 which simultaneously engages the opposite off-center portionof the closure. The endless belt 16 is mounted on a drive pulley 61,idler pulley 62, and a tensioning pulley 64.

The lower run 65 of the endless sealing belt 16 is guided and positionedby a pressure guide 66 (FIGS. 7 and 16) which is mounted on two brackets67 and 68 connected to the top of the enclosure 95 illustrated in FIG.16. The brackets 67 and 68 are connected to bracket connectors 69 whichare adjustably positioned vertically of the enclosure 95 by means of thethreaded connection 70. The upper portion 71 of the brackets 67 and 68is slideably fitted within the connectors 69 and held in a normallydownward position therein by compression springs 72. The compression ordownward force of the spring 72 is set by the pressure control knobs .73which are threadedly connected at the top of the bracket connectors 69.

The fixed shoe 17 is mounted parallel to and on the same general levelas the lower run 65 of the belt 16 by being attached to the beltpressure guide 66 by connector plates 87. Thus the vertical position ofboth the lower run 65 of belt 16 and of the fixed shoe 17 is adjusted bythe bracket connectors 69 and the pressure exerted downwardly on theclosure during the closure tightening action of the cooperating movingbelt 16 and fixed shoe 17 is set by the adjusting pressure control knobs73. When the containers 12 and their respective closures 14 move beneaththe belt 16 and the fixed shoe 17, downward pressure is applied to theclosure 14 by the controlled upward motion of the belt 16 and the shoe17 and the resulting compression of the spring 72 in an amountcontrolled by the presure control handle 73. The simultaneous forwardmovement of the lower run of belt 16 and the frictional drag force ofthe fixed shoe 17 rotate thrust member for the sealing means 15 toposition it longitudinally of the conveyor belt 2. A tensioning arm 81mounted on pinion 80 holds the tensioning pulley 64 in engagement withthe sealing belt 16. The tensioning arm 81 includes telescoping members82 and 84 and a compression spring 85. The amount of spring forceexerted by spring 85 is adjusted by the threaded coupling 86.

The fixed shoe 17 which is positioned outwardly of the belt 16 inposition to engage the closure top is attached to the belt pressureguide 66 by connector plates 87. In order to provide for a heightadjustment of the fixed shoe 17 independently of the belt pressure guide66, adjusting screws 88 are provided on each of the mounting plates 87to lock the relative positions of the plates 87 and the fixed shoe 17 onconnector screw 89 as illustrated in FIG. 7.

In order to provide for a frictional engagement between the fixed shoe17 and the closure 14 a friction lining 90 is riveted or otherwiseattached to the bottom surface of the fixed shoe 17.

As seen in FIG. 5 the lower surface of the fixed shoe 17 preferably hasa relatively horizontal and flat short downwardly projecting centerportion 91 which provides the final degree of downward sealing pressureand assures quick rotation of the closure into its final sealed positionon the container threads while it is subjected to the downward sealingforce. The portions of the shoe 17 leading up to the sealing surface 91comprise a curved end 92 to provide a lead-in section for the movingclosures 14 and a relatively level initial contact portion 93 betweenportions 91 and 92 which bridges the friction member 90 so that it ispermitted to flex upwardly to accommodate it to the closure 14 and toinitiate the closure rotation as the closures 14 move into the finalsealing portion 91.

The belt positioning shoe preferably has similar lead-in and lead-outportions and a fiat center sealing portion 94 which applies the finaltorque and sealing pressure.

In order to prevent rotation of the containers 12 while the closures arebeing screwed into their final sealed position, the side belts 20 and 21are provided. These are mounted on drive pulleys 22 and idler pulleys 23and their container contacting portions are held inwardly against thecontainers by positioning pulleys 24. The pulleys 24 are adjustablymounted on the sides of the enclosure 95 as illustrated in FIGS. 4 and8. In the preferred embodiment, a plurality of pulleys 24 are mounted onsuitable brackets 97 on opposite sides of the conveyor belt 2. A unitarypositioning control is provided for the pulleys 24 so that the singlecontrol handle 96 may be rotated to move the belts to their correctposition above the conveyor for a proper gripping of the containers 12.The brackets 97 for the pulleys are each mounted on the housing 95. Eachof these arms has a rack and pinion connection 100, 101 (FIG. 4) toshafts 102 which are interconnected to each other and to control handle96 by intercoupled shafts 104, 105, and 106 (FIGS. 4 and 9). Rotation ofhandle 96 thus provides for a simultaneous inward or outward movement ofthe belts 29 and 21 laterally of conveyor 2 and the adjustments may bemade while the sealing machine 15 is in operation.

While the machine including the closure feed is primarily designed forthe application of screw closures the cap feed particularly isapplicable for feeding and initially applying any type of closure. Wherethe initial turning or coax-ing is not desired the rubber or frictionrail may be changed to a smooth metal rail corresponding to rail 44.

Where press-on caps are thus used the final seal is made by a downwardpressure which may be provided by using a wider sealing belt in place ofbelt 60 so that the belt covers the lower surface of both of the shoes66 and 17. A wider drive pulley to accommodate the broader belt may besubstituted for 61.

Operation The operation of the improved sealing machine which has beendescribed in connection with the detailed description of the machine andmethod will now be summarized.

As indicated above the sealing machine 1 may be used for a wide varietyof container and closure sizes. Once the container diameter has beendetermined the side rails 9 and the container gripping belts 20 and 21are adjusted for the container diameter. The guide rails 9 arepositioned centrally of the conveyor and the closure applicator means 11and the sealing means 15. The container gripping belts 20 and 21 areadjusted laterally of the conveyor 2 to provide a continuous movement ofthe container on conveyor 2 past the closure applying means 11 and toprevent rotation of the containers 12 as the closures 14 are applied bythe sealing means 15. As described above, the single adjusting knob 96is rotated to move the positioning pulleys 24 laterally of the conveyorbelt 2 to provide the necessary spacing of the belts 29 and 21.

When the container height has been determined an initial verticaladjustment is made of the closure app-lying and sealing means 7 which isvertically movable as a unit on the base 3 by adjustable posts 99 (FIG.4). This adjustment on the post members 99 (FIG. 4) provides for theinitial vertical positioning of both the closure applicator 11 and thesealing means 15.

The sealing means 15 is adjusted independently of the closure applicator11 by rotating the threaded bracket connectors 69 at the top of theenclosure 95. This adjustment is made to position the lower run 65 ofthe sealing belt at the proper height so that it exerts the desiredhorizontal cap rotating force simultaneously with the downward sealingforce. Adjustment of the vertical position of the lower run of the belt16 also places the fixed shoe 17 at about its proper height. Additionalfine adjustments of the height of the shoe 17 are made initially orduring the preliminary test runs by the adjusting screws 88 and 89 (FIG.7) which provide a fine height adjustment for the fixed shoe 17 and alsoadjust both the longitudinal and lateral slope of the friction surface90 of the fixed shoe 17 to provide for the correct frictional force withthe closure caps 14 as the containers 12.draw the closures 14 beneaththe cooperating belt 16 and the shoe 17.

The initial threading of the closure 14 beneath the coaxing plate 42 iscontrolled by the vertical position of the plate 42 and this is set byraising or lowering the adjusting screw 54 (FIG. 13) to increase ordecrease the amount of the initial coaxing rotation applied to theclosure by the plate 42.

In the regular sealing operation of the machine the containers 12 arefed in spaced relationship onto the moving conveyor 2 adjacent endpulley 4. If desired, a suitable additional spacing means may beprovided adjacent conveyor 2 such as a container spacing helicoid.Containers moving on the conveyor 2 are first carried beneath the steamtunnel 10 as illustrated in FIG. 12 and steam issuing downwardly fromthe tunnel enters the container head space and displaces the airtherefrom. Further movement of the containers carries them to the end104 (FIG. 10) of the steam tunnel 10 at which point the nozzle 105directs an additional jet of steam into the head space and also againstthe under side of the lowermost closure 14' in the cap chute 30. Thisinsures the removal of trapped air from the container head space andfrom beneath the closure 14 just prior to the application of the closure14 to the container 12. The closure 14' is loosely applied to thecontainer 12 as illustrated in FIG. 13 by movement of the upper edge 35of the container 12' against the skirt of the lower-most closure 14' inthe cap chute 30 whereby the closure 14' is drawn over the containerfinish and past the detents 34 on the lower end of the cap chute. As thecap is drawn past detents 34 and onto the top of the container 12' themagnetic wheel 38 rotates with the closure 14' so that the closure 14 isheld up against the lowermost surface of the leveling plate 40 and isthus moved to level position on the container finish while telescopedabout the finish and moving forward with the containers.

As the closure 14 is drawn beyond the magnetic wheel 38 additionalmagnets 41 in the leveling plate 40 continue to hold the closure 14" ina level raised position about the top of the container 12". Additionalmovement of the container 12" brings the closure 14" into contact withthe coaxing plate 42 as illustrated in FIG. 15. The top of the closure14" is engaged at spaced positions by the smooth metal rail 44 and therubber friction member 45. This provides a light rotation force whichrotates the closure 14" at least a fraction of the revolution andprovides for an initial light engagement between the threads of theclosure and the container. Continued movement of the conveyor belt 2 nowcarries the containers 12" with its loosely applied closure 14" beneaththe sealing means 15.

The container 12 is located centrally of the sealing means 15 asillustrated in FIG. 7 so that the closure top is simultaneously engagedby the moving belt 16 and the friction member on the lower surface ofthe fixed shoe 17. The initial portions of both the belt and thefriction members are inclined downwardly to provide for a gentleengaging contact between the closure 14 and the belt 16 and frictionmember 17. As described more fully above the moving belt 16 incooperation with the frictional braking action of the fixed shoe 17causes the closure 14 to be screwed downwardly to seal the container.Simultaneously, both the belt 16 and the shoe 17 provide a downwardsealing force which facilitates the sealing action. This downwardpressure is provided by springs 72 (FIG. 16) as described above so thatwhen the container reaches the portion of the belt and the frictionmember in engagement with the flat centers 91 and 94 respectively of theshoes 66 and 17 the combined rotational and downward force aresufficient to screw the closure 14 into sealed position with the properamount of torque.

As illustrated in FIG. 10 an elongated steam tunnel 18 is providedadjacent both the closure applying means 11 and the container sealingmeans 15 so that a sheet of steam envelopes the tops of the containersand the closures to prevent the reentry of air into the containersduring the sealing operation and to insure the creation of the desiredvacuum in the head spaces of the sealed con tainers.

It will be seen that the present invention provides an improvedmechanism for initially threading screw closures, preferably of the lugtype, to glass finishes which avoids cocked caps or crossed threads. Theclosures during initial application are suspended magnetically inpartially telescoped relation to the glass finish as they move with thecontainer. By suspending the closures magnetically they are free to movehorizontally in any direction and to center themselves on the finish. Bymaintaining the closures in a horizontal position cocked caps areavoided. The initially threaded closures pass under a braking shoe whichapplies an effective braking action to screw the closure into finalsealing position. A moving belt engaging the opposite off-centerportions of the closures prevent them from cocking and facilitates theapplication of sufficient torque to provide a secure seal. Both theinitial threading mechanism and the final sealing means are simple inconstruction and effective in operation.

As various changes may be made in the form, construction and arrangementof the parts herein without departing from the spirit and scope of theinvention and Without sacrificing any of its advantages, it is to beunderstood that all matter herein is to be interpreted as illustrativeand not in a limiting sense.

Having thus described my invention I claim:

1. In a machine for sealing containers with screw caps the combinationof an endless belt positioned with its lower run engaging an off-centerportion of closure cap tops seated upon moving containers, drive meansfor said belt adapted to move the lower run at a given speed in thedirection of the moving containers, a shoe mounted adjacent said beltand restrained against movement in the direction of said movingcontainers and positioned to engage opposite off-center portions of saidclosure cap tops and pressure means resiliently urging said lower run ofsaid belt and said shoe downwardly against the closure caps whereby saidbelt and said shoe cooperate to press said closure caps downwardly andto screw them into sealing engagement with containers.

2. A machine for sealing containers with screw caps comprising thecombination of a conveyor to move containers along a generallyhorizontal path, a pair of sealing members mounted above said conveyorto engage opposite off-center portions of closure cap tops seated onmoving containers on said conveyor, one of said sealing memberscomprising a contact shoe and being restrained against movement in thedirection of conveyor movement and the other comprising an endless belt,drive means coupled to said belt and adapted to move it faster than saidconveyor, and pressure means for urging said belt and shoe downwardlyagainst the closure caps seated on containers passing beneath themwhereby said shoe and said belt cooperate to screw the closuresdownwardly onto the containers.

3. In a machine for sealing containers with screw caps, the combinationof a conveyor to move containers along a generally horizontal path, aclosure chute adapted to feed a closure cap to each container on saidconveyor, a pair of spaced elongated rails positioned generally parallelto said path to contact opposite off-center portions of the tops ofclosures on said containers, one of said rails having a greater frictioncoeflicient than the other to initially rotate the closures contacted bysaid rails, an endless belt mounted to engage one of two oppositeelf-center portions of closure cap tops seated on containers on saidconveyor, a shoe mounted adjacent said belt to engage the oppositeoff-center portions of said closure cap tops, and pressure means urgingsaid shoe and said belt downwardly against the closure cap top wherebysaid shoe and said endless belt cooperate to screw the closuresdownwardly onto the containers.

4. The machine as claimed in claim 3 in which the lower surface of saidshoe slopes downwardly from its front and rear ends to a centralgenerally horizontal sealing portion.

5. A sealing machine for sealing containers with threaded-type capscomprising a conveyor adapted to carry a succession of containers in agenerally horizontal path, a cap applicator positioned above saidconveyor adapted to apply closures to the tops of containers being movedtherebelow by said conveyor, and a container sealing means forthereafter screwing the caps onto said containers comprising an endlessbelt positioned above said conveyor and having a lower run aligned tomove in the direction of said conveyor, drive means coupled to said beltadapted to drive it at a given speed, a friction member mounted adjacentto said endless belt and above said conveyor and generally parallel tothe lower run of said endless belt and restrained against movement inthe direction of the conveyor belt path, said endless belt and saidfriction member positioned to engage opposite elf-center portions of theclosure cap top-s.

6. A sealing machine for applying screw caps to containers comprising,in combination, a conveyor adapted to carry a succession of containersin a generally horizontal path, a chute positioned above said conveyoradapted to feed closure caps to the tops of containers being movedtherebelow by said conveyor, a pair of elongated spaced rails positionedgenerally parallel to said path to engage opposite sides of the tops ofclosures on said containers, one of said rails adapted to apply greaterfriction than the other to provide a light closure rotating force torotate the closures into initial engagement with the container threads,an endless belt positioned above said conveyor and having a lower runaligned to move in the direction of said conveyor, a drive for saidendless belt adapted to move it at a given speed, a shoe mountedadjacent said endless belt and above said conveyor and generallyparallel to the lower run of said endless belt and restrained againstmovement laterally and longitudinally of said conveyor, said endlessbelt positioned to engage oll-center portions of the closures on saidmoving containers and said shoe positioned to engage oppositeofli-center portions of said closures to screw them on containers.

7. The machine as claimed in claim 6 in which the lower portion of theshoe slopes downwardly from its front and rear ends to a centralgenerally horizontal sealing portion.

8. The machine as claimed in claim 7 in which the lower strand of theendless belt is forced downwardly by a member having a lower surfacesimilar to the lower surface of said shoe.

9. In a sealing machine for sealing containers with caps of ferrousmetal the combination of an inclined cap chute, a leveling platepivotally mounted on the end of said chute, and a magnetized wheelintermediate the chute and the leveling plate to magnetically engage thetops of the caps and move the caps from said chute to said levelingplate.

10. In a sealing machine the combination of an inclined cap chute, aleveling plate pivotally mounted on the end of said cap chute, amagnetized wheel rotatably mounted intermediate the shoe and theleveling plate to magnetically engage the tops of caps to transfer themfrom said shoe to said leveling plate, and a coaxing plate on the end ofsaid leveling plate mounted for movement vertically with regard to saidleveling plate and having a plurality of cap leveling rails thereonadapted to apply a relatively light downward force to caps leaving saidleveling plate.

11. In a sealing machine, the combination of an inclined cap chute, agenerally horizontal leveling plate pivotally mounted on the end of saidchute, a magnetized wheel rotatably mounted intermediate the chute andthe leveling plate, a magnet on said leveling plate adapted to supportcaps transferred thereto by said magnetized wheel, and a coaxing plateat the end of said leveling plate connected for movement vertically withregard to said leveling plate and having a capretarding friction memberthereon positioned to engage an offcenter portion of caps.

12. In a sealing machine, the combination of a conveyor for containers,an inclined chute positioned above said conveyor to present thelowermost closure therein to the top of a container moving therebelow onthe conveyor, a leveling plate pivotally connected to said chute andhaving a generally horizontal magnetized lower surface adapted to leveland support closures drawn from said chute onto the container mouths, amagnetized wheel rotatably mounted intermediate said chute and saidleveling plate and adapted to support closures being moved by acontainer from the chute to the leveling plate, a coaxing plate at thefree end of said leveling plate and said chute, and closure rotatingmeans on said coaxing plate positioned to engage an oil-center portionof the closures.

13. In a sealing machine the combination of a horizontally disposedcontainer conveyor, an inclined cap chute positioned above said conveyorto present the lowermost closure therein to the top of a containermoving therebelow on the conveyor, a pivotally mounted leveling platehaving a generally horizontal magnetized lower surface adapted to leveland support closures drawn from said chute by the container months, amagnetized wheel rotatably mounted intermediate said chute and saidleveling plate and adapted to suspend closures being moved by acontainer from the chute to the leveling plate, a coaxing plate at thefree end of said leveling plate and pivotally mounted for verticalmotion with respect to said leveling plate and said chute, closurerotating means on said coaxing plate positioned to engage an off-centerportion of the closure tops to provide an initial engagement between thethreads of the closure cap and the container, a pair of sealing memberspositioned above the conveyor beyond said coaxing plate to engageopposite off-center portions of the closure caps, one of said sealingmembers comprising an endless belt movable in the direction of themoving containers, the other sealing member comprising a stationaryshoe.

14. The method of applying a screw cap to a container which comprisesthe steps of loosely threading the cap to the top of the container, andthereafter moving the container to carry an off-center portion of thetop of the cap into sliding frictional engagement with an elongatedstationary member and an opposite ofi-center portion into frictionalengagement with a moving endless belt, moving said endless belt at aspeed greater than the speed of the moving container and in the samedirection, and simultaneously applying downwardly directed pressureagainst the cap top by said stationary member and said belt member.

15. The method as claimed in claim 14 in which said pressure is intenseand is applied for a very short period.

16. In a sealing machine for applying caps to containers the combinationof an inclined cap chute, a cap leveling plate pivotally mounted on theend of said chute, a magnetized wheel rotatably mounted intermediatesaid chute and said leveling plate to engage the tops of caps and totransfer them from said chute to said leveling plate, and saidmagnetized wheel comprising spaced circular plates of magnetic materialengaging the opposite poles of a plurality of magnets, and said magnetshaving their north poles adjacent the same one of said plates and theirsouth poles adjacent the other of said plates.

17. In a sealing machine for applying caps to containers the combinationof an inclined cap chute, a cap leveling plate pivotally mounted on theend of said chute, a magnetized wheel rotatably mounted intermediatesaid chute and said leveling plate to engage the tops of caps and totransfer them from said chute to said leveling plate, and saidmagnetized wheel comprising a nonmagnetic disc-like center portionmounting one or more magnets, the opposite circular ends of said centerportion having circular plates of magnetic material mounted thereon witha diameter greater than said disc and said magnet having its north poleadjacent one of said plates and its south pole adjacent the other plate.

18. In a machine for sealing containers with screw caps the combinationof an endless belt positioned with its lower run engaging an oif-centerportion of closure cap tops seated upon moving containers, drive meansfor said belt adapted to move the lower run in the direction of themoving containers, a braking member mounted adjacent said belt andhaving a friction surface for engaging and retarding opposite off-centerportions of said closure cap tops, and pressure means resiliently urgingsaid lower run of said belt and said braking member downwardly againstthe closure caps whereby said belt and said braking member cooperate topress said closure caps downwardly and to screw them into sealingengagement with containers.

References Cited in the file of this patent UNITED STATES PATENTS1,664,514 Kramer Apr. 3, 1928 2,041,891 White May 26, 1936 2,072,245Cuthhert et a1 Mar. 2, 1937 2,440,030 Thomas Apr. 20, 1948 2,630,959Brown Mar. 10, 1953 2,876,605 McElroy et a1 Mar. 10, 1959 3,012,388Stover Dec. 12, 1961

